1. Field of the Invention
This invention relates generally to insulated thermal cooking devices, and more particularly concerns a system and method for controlling adiabatic cooking in an insulated adiabatic cooking apparatus, such as for use as a home cooking apparatus.
2. Description of Related Art
Energy conserving cooking presently can be accomplished with conventional insulated adiabatic cookers that are not directly heated by an internal or external source of heat, but that are insulated to significantly slow heat loss in order to allow the food or other items to continue to cook due to the retention of heat from preheating prior to placement in the adiabatic cooker. Such cookers typically consist of an inner pot with a cover made of stainless steel, and a thermally insulated outer container, typically also having a cover made of stainless steel, or a combination of plastic and stainless steel. For purposes of this application, adiabatic cooking is defined herein as cooking of food or other items with minimal heat gain or loss, by heat retained from preheating of the food or other items to be cooked. Currently, all such commercially available cookers can be grouped as to the two basic types of insulation they utilize. One type of insulated adiabatic cooker utilizes a vacuum to provide insulation, and another type utilizes a layer of an insulating material, such as a polyurethane material.
Such insulated adiabatic cookers are usually operated by first boiling the food in the inner pot on an external stove for a specific length of time, depending upon the type of food being cooked. After the specific boiling time is reached, the inner pot is placed into an insulated outer container for additional cooking by using the heat in the inner pot, generated from initially boiling the food. This type of cooking is commonly known as "Thermo Cooking", and one such type of insulated adiabatic cooker is available under the trade name "Thermo Cooker." Such thermally insulated adiabatic cooking containers commonly have good heat insulating characteristics such that the food in the inner pot can be maintained at a temperature above 90 degrees centigrade for up to two hours when the inner pot is placed in the thermally insulated outer container. Food typically continues to be cooked when the temperature of the food is 90 degrees centigrade or higher.
Such conventional thermally insulated adiabatic cookers frequently have several shortcomings. For example, the cooking of the food in the inner pot must be supervised, both while the food in the inner pot is heated to bring it to a boil, and subsequently while the contents are boiled for the specific boiling time required for the specific food being cooked, such as 5 minutes for the chicken, 15 minutes for the beef or lamb, etc. This can be a very troublesome task for a person performing the cooking.
Another disadvantage is that after the food has been initially boiled in the inner pot, the hot inner pot must be transferred to the thermally insulated container. The inner pot at this time is very hot and dangerous to move.
In addition, when a conventional thermally insulated adiabatic cooker is to be used to cook food, the container is typically at room temperature. After the inner pot is brought to a boil and put into the insulated container, the outer insulated container will absorb heat from the inner pot until the temperature of the inside of the outer container is the same as the inner pot temperature. As much as five degrees centigrade of heat or more can be dissipated from the inner pot in this manner during the first hour, which is a very large loss of heat, especially since the heat is needed most during the first hour to permit adiabatic cooking.
Furthermore, when the food is adiabatically cooked in the insulated container, one has to remember or write down the time the adiabatic cooking begins, and watch the cooking time. Different foods require different adiabatic cooking times, such as 15 minutes for vegetables, 30 minutes for fish, 60 minutes for chicken or pork, and 90 minutes for the beef and lamb, and the like. In order to avoid overcooking of the food, the adiabatic cooking time in the insulated container has to be monitored closely.
In addition, when cooked food is left in the thermally insulated adiabatic cooker for more than 8 hours, the food can spoil, because the temperature of the food can fall below 70 degrees centigrade. Bacteria can grow in food when the temperature of the food is below than 70 degrees centigrade, so that any food left in the adiabatic cooker when the temperature falls below 70 degrees centigrade needs to be either refrigerated, or brought to a temperature above 70 degrees centigrade again in the inner pot, if the food is to be kept in the insulated container, either of which can be a troublesome task. Therefore, food left in such conventional cookers after the temperature in the cooker falls below 70 degrees centigrade can easily spoil.
It would therefore be desirable to provide a fully automatic thermally insulated combination active and adiabatic cooker and a method of cooking, that can provide solutions to the foregoing problems of conventional insulated adiabatic cookers, and that can provide for savings of time and energy, environmental friendliness, and multi-functionality, and that can cook with or without internal heat being supplied by the cooker. The present invention meets these needs.